Simple Woodturning Tools - 1&frac14;" X 8 TPI Vacuum Chuck for Woodturning Lathe Bowl Turning American Made and Customer Supported by Harrison Specialties , a family owned CNC machining and manufacturing facility in the land of 10,000 lakes - Minnesota. This vacuum chuck gives you a great way to finish the bottom of your bowls and other turned vessels. Outside diameter: 3" Steel tube length: 18" beyond the end of the chuck. Chuck material: 6061 aircraft aluminum Watch our Simple Vacuum Chuck Demo YouTube Video to see it work!